This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To improve our understanding of serotonin-related neural mechanisms regulating female sexual response in marmosets in order to develop more appropriate clinical intervention for sexual hypofunction in women. Sexual dysfunction affects an estimated 43% of women. Currently there are no approved drug therapies for this disorder. Safety concerns about hormonal treatment with estrogens and progestogens motivates the search for non-steroidal pharmoacotherapy. The serotonin neuronal system has been implicated in regulating sexual behavior in a range of female mammals, including humans and nonhuman primates, but the mechanisms involved are not well understood. We have developed a model system with female common marmosets to demonstrate that a serotonin analogue, 8-hydroxyDPAT, diminishes female acceptance of male sexual advances, while another, flibanserin, does not. Flibanserin also enhances positive social interactions between male-female pairs, including grooming. Non-invasive PET brain imaging suggests specific changes in female neural activity associated with the different behavioral outcomes for each serotonin drug. The different serotonin receptor binding properties of each drug are starting to provide clues as to neural mechanisms of action and theraputic application. Publications are pending. This research used WNPRC Assay Services and Animal Services.